Light-transmitting apparatus



May 26, 1959 A. NYMAN Y 2,888,516

l LIGHT-TRANSMITTING APPARATUS Original Filed June 18. 1951 5Sheets-Sheet 1 l l l l l l l Iwelzvfar zZezazza/er JV 775mb @W W W@ May26, 1959 A. NYMAN 2,888,516

LIGHT-TRANSMITTING APPARATUS` Original Filed June 18, 1951 5Sheets-Shes*l 2 May 26, .1959 `A. NYMAN LIGHT-TRANSMITTING APPARATUS 5sheets-sheet s original Filed June is. 1951 May 26, 1959 A. NYMANLIGHT-TRANSMITTING APPARATUS OriginalV Filed June 18, 1951 5Sheets-Sheetv 4 v May 26, 1959 Original Filed June 18.

/ Awww/Pf A. NYMAN LIGHT-TRASMITTING APPARATUS 5 Sheets-Sheet 5Api/Pfam? //A af 2,888,516 Patented May 26, 1959 nice HGHT-TRANSMlTTINGAPPARATUS Alexander Nyman, Dover, Mass., assignor to Alden Prod- :hctsgg., Brockton, Mass., a corporation of Massause` Claims. (Cl. 178-7.6)

'Ihis application is a division of my copending applicanon Serial No.232,221, now United States Patent No.

2,750,443, issued June l2, 1956.

This invention relates to a device for collecting light throughout awide arc, and more particularly to an aperture assembly for collectingthe light and directing it to a photocell or other device. The inventionis especially applicable to scanning apparatus where light iscontinuously collected from different angles.

Objects of the invention are to provide optical apparatus which collectslight equally well at various angles of approach throughout a wide anglewithout moving the collector and more particularly to direct light fromvarious points of a sheet through the aperture of a photocell or thelike without moving either the sheet or the cell. According to thepresent invention the apparatus comprises a light-transmitting elementof a material having a high index of refraction one end of the elementbeing in the form of a wedge together with means for directing lightinto the aforesaid end throughout an arc extending transversely of theapex of the wedge.

The light directing means may comprise a mirror movable throughout anarc extending transversely of the apex of the wedge.

In a more specific aspect the apparatus comprises an aperture assemblyincluding an opaque member having an opening therein characterized inthat the aforesaid wedge extends into the opening so that light rays inplanes normal to the edge of the wedge over a wide incident angle aredirected through the opening. The opening is preferably in the form of aslot extending lengthwise of the apex of the wedge. In the preferredembodiment the aperture assembly comprises two opaque memberseach ofwhich has a slot therein, the members being arranged with the slotslying adjacent each other in angular. relationship so that the widths ofthe slots form the respective dimensions of the aperture, the wedge endof4 the light-transmitting element extending through therearslot. A

. For the purpose of illustration a typical embodiment of the. inventionis shownfin the accompanying drawings in which: M l l `Fig. 1 is a.front elevation-view of a facsimile scanner;

Fig. 2 is a side elevation view of the scanner shown inEg 1; y'g' Fig. 3is-agpartial plan view of the copy table;

Fig. 4 is a partial section on lines 4-4 of Fig. 3;

,Fig. l5 is afll'sartial..sectional4 view on lines 5-5 of Fig. 6 is afront elevation view on the spider andmirror assembly; 'i

Fig. 7 -is a side elevation view of the spider and mirror assembly; .v

Fig; 8v is a front elevation lview of one construction of the apertureassembly; 4 f

Fig. 9 is a sec'onalview on lines 9-9 of Fig. 8;

" Fig. 9a is a sectional view similar to Fig. 9 of an alternateconstruction of aperture assembly;

Fig. 10 is an enlarged partial sectional view showing the details of theaperture plates; and

Fig. ll is a schematic diagram illustrating the principle of operationof the scanner. r

As is best shown in Figs. l and 2 the embodiment of an optical scannerchosen for the purposes of illustration is supported upon a base 20having a bracket 24 cast integrally therewith so that the bracketextends upwardly from the rear of the base. The bracket 24 has bosses 26positioned at either end thereof wherein are carried respectively twovertically disposed columns 28 which telescope respectively in aperturesin the bosses being secured in adjusted position by means of thumbscrews 30.

Upon the upper ends of the columns 28 is carried a copy table 32, whichhas an upper copy guiding surface 34, each side of which is reinforcedby a respective rib 36 being attached thereto by means of screws 38. Atthe rear end of each rib 36 is an integrally cast nger or tab 40 whichis turned inwardly and provided with an aperture for engaging the upperend of a respective column 28. The table 32 is held in position by twopairs of nuts 42 and 44 which engage threads cut in the ends of thevcolumns 28 so that nuts are positioned respectively above and belowthev tabs 40.

As is shown in Figs. 3 and 4, the surface 34 of the cop'y table 32 isprovided with three transverse slots. The centerslot A, which forms anelongated optical aperture whose function will be described in detailbelow, is brightly illuminated from the bottom of the table by means oftwo tubular electric lamps L which are preferably of the fluorescenttype. The lamps L are enclosed in a lamp housing 45 which is suspended beneath the table 32. The housing 45 consists of a substantiallyrectangular frame having two opposed side members 46 which are providedwith a plurality of apertured tabs 48. Connecting members 47 extendbetween the ends of the side members 46 to complete the frame. Aplurality of knurled headed screws 50 engage the corresponding tabapertures and thread into the bottom of the table so that the housing 45is secured to the table 32. A sheet metal enclosure 52, which is shapedlike an inverted V as is best shown in Fig. 4, is attached to the frameside members 46 by screws 53. Suitable electrical elements ofconventional design such as the sockets and connectors designatedgenerally by the numeral 54 are located at the lower end of each of thelegs of the housing to accommodate the respective lamps L. A slottedaperture A is positioned at the apex of the enclosed legs where itis invertical alignment with the table aperture A.

The lamp housing 45 also supports two pair of copy feed rolls which arelocated in the outer slots in the table on either side of the apertureA. The upper driven roll 56 is carried upon a shaft which is journaledlin bearings 58 as is shown in Fig. 5. Each bearing 58 is pressed intoan aperture in a respective boss 60 which projects upwardly through theslotted apertures in the table from the connecting members 47 of thelamp housing 45. The shaft of the lower driving roll 62 is journaled inbearings 64 pressed in apertures in the opposed connecting members 47immediately below the bosses 60.

Both pairs of feed rolls are driven at the same speed by means of anelectric motor M which is suspended :from the bottom of the housing 68of a reduction gear unit by means of the knurled screws 66. The gearreduction unit comprises a shaft 78 whose ends are journaled in bearings80 (Fig. 3) pressed in the housing ends 70. The shaft 78 carries twoworms 82 which engage gears 84 carried on the ends of the respectiveshafts of the lower v .feed rolls 62'. interposed between the worms 82is a driving gear 86 which mates with a worm gear 88 carried to the endof the motor shaft. The pinion`100 mates with a gear 102 carried upon -ashaft 104 journaled in the walls of the vhousing 98. vThe end of theshaft 104` extends through 'the front housing wall and carries a disc105 which is secured to the hub 106 of a spider 103vby means of threescrews 110.

As is shown in`Figs. 6 and 7, the spider 108 consists of a structurewhich may be either cast or fabricated in the form of an octagonal rim114 having a iiange 112.

` Eight equally spaced integral spokes 116 cant outwardly from the hub106 to the respective junctions between adjacent at portions of theoctagonal rim 114. A plurality of mirrors 115 (Fig. l) are carried uponthe respective at portions of the rim portion 114 being secured theretowith their reecting surfaces directed inwardly by associated brackets118 which are attached to the spider 108 by means of screws 120.

-A stationary mirror 122 isepivotally mounted upgn the base 20 directlybelow-the aligned apertures A and A'. The mirror 122 is secured in abracket 123 journaled in two bosses -124 extending upwardly from thebase 20 so that it can'bc adjusted by means of a spring biased adjustingscrew 126 to impinge light rays coming from the subject copy adjacentthe table aperture A upon the particular spider mirror 115 which ispositioned in the top portion 'of its travel about the axis of the shaft104.v A conventional converging lens system is mounted inthe opticalbarrel 128 which is supported between two spaced brackets 129 extendingupwardly from the front portion of the base 20 so that the lens systemis interposed in the optical path between the stationary mirror 122 andvthe top spider mirror 115.

A second stationary mirror 130 (Fig. 2) is supported y A by means of abracket 132 within the rim 114 of the spider 108 directly beneath theposition occupied by theA top spider mirror 115. The ends of the bracket32 are provided with slots through which pass screws 134 engagingthreaded apertures in the sides of a boss 136 extending from a phototubehousing 138 whereby the position of the mirror can be adjusted withrespect to the surfaces of the spider mirrors 115.

A light sensitive device such as the photocell P is mounted in ahorizontal position within the hollow light tight housing 138. Lightrays reflected from the mirror 130 are admitted into the housing 138through an aperture 140 secured in the boss 132. The structural detailsOf one form of the aperture assembly can best be seen in Figs. 8 throughl0 wherein the numeral 142 designated as a anged cylindrical member orbarrel having an axially disposed passage or aperture extendingtherethrough. A rod 148 of a material, such as sapphire, having a highindex of refraction is inserted in the passage. One end of therod 148 isground in the shape o'f a wedge with diverging surfaces of equal areahaving an included angle of approximately 40 as is 'shown in Fig. 10.The wedge shaped end of the rod 148 extends beyond the end of the barrel-142 through a V-shaped slot milled or otherwise cut in a strap 150 atan angle of 45 to the longitudinalaxisofthe strap asisshowninFig. 8. The150 is recessed in a groove inthe flanged end of the brrel 142 beingsecured therein by means of screws 152 which engage threaded aperturesin the flange. A second similarly-slotted strap 154 is fastened to theflanged end of the barrel 142 by screws 155 so that the slot thereinlies adjacent and 'atan angle of 90' 'tothe slot inthe recessed strap150. The depth of the groove in the end of the barrel 142 is madeslightly greater than the thickness of the strap 150 so thata clearanceis provided between the straps 150 and 154 into which clearance thc apexof the wedge end of the rod 148 extends as is shown in Fig. l0. The rod148 is held in position by means cf a transparent plate 157 which issecured in a recess in the end of the barrel 142 by means of screws 159.

As is best shown in Fig. 8 the edge of the wedge end of the rod 148 isarranged parallel with .the axis of the slot' in the bottomniost strap150 so that light rays nor mal to the edge impinge upon the wedge over-a great angle of incidence approaching 120 without appreciable loss ofaperture area, that is, as shown in Fig. 11, the rod 148 is sopositioned that as each mirror swings across the light path, from theposition II in Fig. 1l to a corrponding position on the other side ofthe vertical, the light enters the wedge Aiirst on one side and then onthe other. The effective dimensions of the aperture are dctermined bythev width of the slots in the straps 150 and 154.

A modification of the aperture assembly is shown in Fig. 9a wherein thegrooved straps 150 and 154 and the wedge shaped end of the sapphire rodaresimilar in-construction to-thcse described in detail heretofore. Therod 148a is 'foreshorted and abuts the small end of a truncated cone 144of alight transmitting material auch` as Lucite which is secured in atapered aperture'in the barrel 142e by means of screws 146.

The aperture barrel 142 is mountedin the 'boss 136 with the axis of thegroove in'theoutside strap 154 perpendicular to the optical axis of lens128 and parallel to .the retleeting surface of the top spider mirror 115-in v its median position so that the wedge at--the end of the the motorM1, the image band or strip rod 148 will receive incident lighdthrough-dialers! wide angle on either side of the apertureaxis. r'

The housing 138 for the photooeil -P'is secured vto the face of abracket 160 (Fig. 2) by means of screws '162.' The bracket 160 is inturn attached to 'the horizontal boss 166 on the top of the rear basebracket 24 by means of screws 168. The end of the housing 138 isprovided with a flange to which is fastened a side plate 164 (Fig. 1).'The side plate 164 has mounted on its inner surface a conventionalsocket (not shown) so that the photocell P is readily taken from thehousing 138 by removing the plate.

The copy is placed upon the top of the table 32 and manually insertedbetween the two pair of feed rolls 56 and 62 with the surface to bescanned towards the table surface 34. The cnergization of the motor Mdrives both pair of feed rolls, as described heretofore, Yso that thesubject copy moves by the aperture slot A in the table surface 34. Lightrays from the lamps L are reliected from the portion of the copyadjacent the aperture A, vdown through the opening A', in the lamp'enclosure 45 to impinge upon the stationary mirror 122. The rays arethen reflected Afrom the mirror 122 'through the converging lens systemin the barrel '128 to impinge upon the mirror which is positioned at thetop of the path of travel and thence tothe stationary mirror whichdirects the rays through the' aperture to impinge on the light sensitiveelectrode of the photocell P.

It will be evident that as the spider 108 is of light reflected fromIthe copy adjacent the aperture A as described above, moves acro thewedge "at the end 'o'f the sap-v phire rod148ofthe'aperture 140.e.thephotocellP in etect sees sueeessive elemental ofthecopy. Bycorrelating the rate of advance of the 4copywiththe rotational speed ofthe spider 108, each oessive mirror 11S xeects light rays fromsequential transverse elements of the 'copy so that the photocelll?receives light from successive areaso'f 'sequential transverse elementsof the subject copy the. the copy s scanned by the photooell.

A schematic diagram is shown in Fig. 1l wherein for clarity andsimplicity the stationary mirrors 122 and 130 and the spider mirrorsother than the one of immediate concern have been omitted. In thediagram the aperture and the spider mirror bear the designations 140 and112 respectively as employed previously heretofore. With the mirror 112in the uppermost position designated I, the image of the aperture 140,appears to be at a distance behind the mirror surface equal to H1 i.e.the distance between the mirror surface and the aperture. The distancebetween the aperture 140 and the axis of rotation of the mirror spiderabout the shaft 104 is designated D. If there is a stationary mirrorbetween the rotating mirror and the axis (such as 130 in Figs. 1 and 2)D is the distance between the axis and the virtual image of the aperturebehind the stationary mirror, and if there is no such stationary mirrorD is the actual distance as in Fig. ll. It will be evident that Hl-l-Dis equal to the radius of rotation of the spider mirrors.

If the mirror 112 is rotated clockwise through an angle to a positiondesignated II, the aperture image is also moved through the same angleto a position which appears to be a distance behind the mirror surfaceequal to H2 i.e. the distance from the aperture 140 to the mirrorsurface. During such rotation the aperture image deviates from astraight line by a distance designated x i.e. the effective location ofthe aperture changes with the rotation of the mirror 112 so that thelight rays coming from the copy through the lens system 128 cannot bemaintained in focus upon the aperture.

Fromthe geometry of the diagram it will' be evident that the followingrelation holds for any value of a:

X=2D(1-cos a) (H/D-cos a) Further it can be shown both experimentallyand mathematically that for any given maximum value a of the angle ofrotation of the spider mirror, by making the ratio H/D equal to cosineof a the deviation x is minimized so that the defocusing can be keptwithin reasonable limits Without the necessity of using special andexpensive lens systems.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

l. Optical facsimile apparatus comprising a support for facsimile copy,`a light-transmitting element of a material having a high index ofrefraction, one end of the element being in the form of a Wedge, and amirror movable throughout an arc extending transversely of the wedge forreflecting an image of said copy on said wedge end from various pointson said arc and means to move said mirror thereby to move the image ofsaid copy across the wedge, said wedge having at least two lighttransmitting surfaces substantially equal in area and converging in anapex directed toward said arc intermediate the ends thereof so that saidwedge presents a substantially constant area to light received fromdifferent points on said arc.

2. Optical lfacsimile apparatus comprising a support for facsimile copy,a light-transmitting element of a material hafving a high index ofrefraction, one end of the element being in the form of a wedge, and aprojector including a converging lens for focusing an image of said copyon said wedge and a mirror movable throughout an arc extendingtransversely of the wedge for reflecting l tion, one end of said elementbeing in the form of a Wedge which extends 'into said slot, and aprojector in cluding a converging lens `for focusing an image of saidcopy on said members and a mirror movable throughout an arc extendingtransversely of the wedge for reecting an image of said copy on saidmembers thereby, and means to move said mirror to move the image of thecopy across said member whereby light rays in planes normal to the edgeof said wedge over a wide incident angle are directed through theaperture, said wedge having at least tWo light transmitting surfacessubstantially equal in area and converging in an apex approximatelybisecting said wide angle so that said wedge presents a substantiallyconstant area to light rays received from different directions withinsaid inci dent angle, and said slot defining one transverse dimension oflight rays falling on said Wedge.

4. Optical facsimile apparatus comprising a support for facsimile copy,an aperture assembly for receiving light over a wide incident anglecomprising two opaque members each of which has a slot therethrough,said members being arranged with the slots lying adjacent each other inangular relationship so that the widths of the slots form the respectivedimensions of the aperture, and a light-transmitting element having ahigh index of refraction, one end of said element being in the form of awedge which extends into said slot, and a projector including aconverging lens for focusing an image of said copy on said members and amirror `movable throughout an arc extending transversely of the wedgefor reflecting an image of said copy on said members, and means to movesaid mirror thereby to move the image of the copy across said memberswhereby light rays in planes normal to the edge of said Wedge over awide incident angle are directed through said aperture, said wedgehaving at least tWo light transmitting surfaces substantially equal inarea and converging in an apex approximately bisecting said incidentangle so that said Wedge presents a substantially constant area to lightrays received from different directions within said wide angle, and saidslots dening the two transverse dimensions of light rays falling on saidwedge. f

5. Optical scanning apparatus for a subject copy com'- prising a lightpickup device; a mirror disposed at a distance from an axis of rotation,means for rotating the mirror about the axis, an optical systemincluding a lens for causing light rays coming from the copy to impingeupon the mirror during a portion of its rotation about the axis, saidoptical system being arranged to image successively the consecutiveelements of the copy upon the device, said device including aperturemeans comprising an opaque member having a rectilinear slotapproximately in the plane of said axis and a lighttransmitting elementhaving a high index of refraction, one end of the element comprising awedge extending into said slot, whereby light rays are directed throughsaid aperture from throughout a wide incident angle, said wedge havingat least two light transmitting surfaces substantially equal in area andconverging in an apex approximately bisecting said incident angle sothat said wedge presents a substantially constant area to light raysreceived from diierent directions within said wide angle, and said slotdefining one transverse dimension of light rays falling on said wedge.

6. Optical scanning apparatus for a subject copy comprising a lightpickup device, a mirror disposed at a distance from an axis of rotation,means for rotating the mirror about the axis, an optical systemincluding a lens for causing light rays coming from the copy to impingeupon the mirror during a portion of its rotation about the axis, saidoptical system being arranged to image successively the consecutiveelements of the copy upon the device, said device comprising maskingmeans and a light-transmissive element, said masking means comprisingtwo opaque members each of which has a slot therethrough, said membersbeing arranged with the slots lying adjacent each other in angularrelationship, the rear slot being approximately in the plane of saidaxis, and said light-transmissive element having a high index ofrefraction, one end of the element comprising a wedge extending intosaid rear slot, whereby light rays are directed through said aperturefrom throughout a wide incident angle, said wedge having at least twolight-transmitting surfaces substantially equal in area and convergingin an apex approximately bisecting said wide angle so that said wedgepresents a substantially constant area to light rays received fromdifferent directions within said wide angle, and said slots dening thetwo transverse dimensions of light rays falling on said wedge.

7. Optical apparatus comprising a light-transmitting element of amaterial having a high index of refraction, one end of the element beingin the form of a wedge, and means for directing a moving beam of lightinto said end throughout an arc extending transversely of the apex ofsaid wedge, said wedge having at least two light transmitting surfacessubstantially equal in area and converging in an apex directed towardsaid arc intermediate the ends thereof so that said wedge presents asubstantially constant area to light received from diiferent points onsaid arc.

8. Optical apparatus comprising a light-transmitting element of amaterial having a high index of refraction, one end of the element beingin the form of a Wedge, and a mirror movable throughout an arc extendingtransversely of the apex of the wedge for directing light into said end,said wedge having at least two light-transmitting surfaces substantiallyequal in area and converging in an apex directed toward said arcintermediate the ends thereof so that said Wedge presents asubstantially constant area to light received from different points onsaid arc.

9. Optical scanning apparatus for a subject copy comprising a lightsensitive device responsive to variations in light intensity, a mirrordisposed at a distance from an axis of rotation, means for rotating themirror about the axis, an optical system including a lens for causinglight rays coming from the copy to impinge upon the mirror during aportion of its rotation about the axis, said optical system beingarranged to image successively the consecutive elements of the copy uponthe device, aperture means comprising an opaque member having arectilinear slot approximately in the plane of said axis, and alighttransmitting element having a high index of refraction, one end ofthe element comprising a wedge extending into said slot, and directedtoward a point intermediate the ends of said portion 0f mirror rotation,whereby light rays are directed through said aperture throughout a wideangle of rotation of said mirror.

l0. Optical scanning apparatus for a subject copy comprising a lightsensitive device responsive to variations in light intensity, a mirrordisposed at a distance from an axis of rotation, means for rotating themirror about the axis, an optical system including a lens for causinglight rays coming from the copy to impinge upon the mirror during aportion of its rotation about the axis, said optical system beingarranged to image successively the consecutive elements of the copy uponthe device, aperture means comprising two opaque members each of whichhas a slot therethrough, said members being arranged with the slotslying adjacent each other in angular relationship, the rear slot beingapproximately in the plane of said axis, and a light-transmissiveelement having a high index of refraction, one end of the elementcomprising a wedge extending into said rear slot, and directed toward apoint intermediate the ends of said portion of mirror rotation, wherebylight rays are directed through said aperture thoughout a wide angle ofrotation of said mirror.

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